Patch from Nick Piggin <piggin@cyberone.com.au>
drivers/block/as-iosched.c | 32 +++++++++++++++++++-------------
1 files changed, 19 insertions(+), 13 deletions(-)
diff -puN drivers/block/as-iosched.c~as-np-reads-1 drivers/block/as-iosched.c
--- 25/drivers/block/as-iosched.c~as-np-reads-1 2003-03-18 01:43:48.000000000 -0800
+++ 25-akpm/drivers/block/as-iosched.c 2003-03-18 01:43:51.000000000 -0800
@@ -38,6 +38,7 @@ struct ant_stats {
int broken_by_write;
int exitted_tasks;
int queued_request;
+ int dispatched_request;
int big_thinktime;
int ant_delay_hist[100]; /* milliseconds */
@@ -686,7 +687,7 @@ static int as_close_req(struct as_data *
sector_t next = arq->request->sector;
sector_t delta; /* acceptable close offset (in sectors) */
- if (ad->antic_status == ANTIC_OFF || ad->antic_status == ANTIC_WAIT_REQ)
+ if (ad->antic_status == ANTIC_OFF || !ad->aic_finished)
delay = 0;
else
delay = ((jiffies - ad->antic_start) * 1000) / HZ;
@@ -718,27 +719,27 @@ static int as_can_break_anticipation(str
{
struct as_io_context *aic;
- if (ad->antic_status == ANTIC_WAIT_NEXT && as_antic_expired(ad)) {
+ if (rq_data_dir(arq->request) == READ && as_close_req(ad, arq)) {
+ ant_stats.close_requests++;
+ return 1;
+ }
+
+ if (ad->aic_finished && as_antic_expired(ad)) {
/*
* In this situation status should really be FINISHED,
* however the timer hasn't had the chance to run yet.
*/
+ ant_stats.timeouts++;
return 1;
}
- if (rq_data_dir(arq->request) == READ && as_close_req(ad, arq)) {
- ant_stats.close_requests++;
- return 1;
- }
-
- if (ad->as_io_context == arq->as_io_context) {
+ aic = ad->as_io_context;
+ if (aic == arq->as_io_context) {
ant_stats.matching_ids++;
if (rq_data_dir(arq->request) == WRITE)
ant_stats.broken_by_write++;
return 1;
}
-
- aic = ad->as_io_context;
if (aic && !test_bit(AS_TASK_RUNNING, &aic->state)) {
ant_stats.exitted_tasks++;
return 1;
@@ -749,6 +750,11 @@ static int as_can_break_anticipation(str
return 1;
}
+ if (aic && atomic_read(&aic->nr_dispatched) > 0) {
+ ant_stats.dispatched_request++;
+ return 1;
+ }
+
if (aic && aic->mean_thinktime > max(HZ/200, 1)) {
ant_stats.big_thinktime++;
return 1;
@@ -975,7 +981,7 @@ static void as_remove_dispatched_request
aic = arq->as_io_context;
if (aic) {
WARN_ON(!atomic_read(&aic->nr_dispatched));
- atomic_dec(&arq->as_io_context->nr_dispatched);
+ atomic_dec(&aic->nr_dispatched);
}
}
}
@@ -1064,9 +1070,9 @@ static void as_move_to_dispatch(struct a
if (data_dir == READ) {
/* In case we have to anticipate after this */
copy_as_io_context(&ad->as_io_context, &arq->as_io_context);
- ad->aic_finished = 0;
} else
put_as_io_context(&ad->as_io_context);
+ ad->aic_finished = 0;
ad->next_arq[data_dir] = as_find_next_arq(ad, arq);
@@ -1212,9 +1218,9 @@ static void as_add_request(struct as_dat
const int data_dir = rq_data_dir(arq->request);
arq->as_io_context = get_as_io_context();
+
if (arq->as_io_context) {
atomic_inc(&arq->as_io_context->nr_queued);
-
if (data_dir == READ)
as_update_iohist(arq->as_io_context);
}
_